Structural Transformation from Dimerization to Tetramerization of Serine-Decorated Rare-Earth-Incorporated Arsenotungstates Induced by the Usage of Rare-Earth Salts.

Three types of serine-decorated rare- earth-containing arsenotungstate [H2 N(CH3 )2 ]6 NaH[RE2 W4 O10 (H2 O)8 (Ser)2 (B-α-AsW9 O33 )2 ]⋅30 H2 O (RE3+ =Eu3+ , Gd3+ , Tb3+ , Dy3+ , Ho3+ , Er3+ , Tm3+ , Yb3+ , and Y3+ ; 1), [H2 N(CH3 )2 ]6 Na6-x REx H4-2 x [RE4 W8 O19 (H2 O)10+y (OH)2 (Ser)2 (B-α-AsW9 O33 )4 ]⋅n H2 O (RE3+ =Tb3+ , x=1, y=2, n=36; RE3+ =Dy3+ , Ho3+ , Er3+ , Yb3+ , Y3+ , x=0, y=0, n=38; RE3+ = Tm3+ , x=1, y=0, n=38; Ser=serine; 2), and [H2 N(CH3 )2 ]6-2 x Na2+3 x REx H10-6 x+y [RE4 W8 O19 (H2 O)8 (OH)2 (Ser)4 (B-α-AsW9 O33 )4 ]⋅Cly ⋅n H2 O (RE3+ =Ce3+ , Pr3+ , x=1, y=0, n=65; RE3+ =Nd3+ , Sm3+ , x=0, y=0, n=65; RE3+ =Eu3+ , Gd3+ , x=1, y=2, n=45; 3) were synthesized with the participation of the organic solubilizers dimethylamine hydrochloride and l-serine and were structurally characterized. The use of different amounts of rare-earth salts results in the structural transformation from dimerization to tetramerization of types 1-3. Type 1 is a dimeric sandwich-type assembly of a dual-Ser-participating [RE2 W4 O10 (H2 O)8 (Ser)2 ]10+ entity sandwiched by two [B-α-AsW9 O33 ]9- moieties, whereas types 2 and 3 have a tetrameric square structure formed by four [B-α-AsW9 O33 ]9- moieties that anchor a dual/tetra- Ser-participating [RE4 W8 O19 (H2 O)10+y (OH)2 (Ser)2 ]20+ or [RE4 W8 O19 (H2 O)8 (OH)2 (Ser)4 ]20+ core. The solid-state luminescence properties and lifetime-decay behaviors of these compounds were investigated. The chromaticity coordinates, dominant wavelengths, color purities, and correlated color temperatures were also calculated.